Meaning

• Any of the joints between the phalanges of the fingers.

• (by extension) A mechanical joint.

• A cut of meat.

• The curved part of the cushion at the entrance to the pockets on a cue sports table.

• The kneejoint of a quadruped, especially of a calf; formerly used of the kneejoint of a human being.

• The joint of a plant.

• A convex portion of a vessel's figure where a sudden change of shape occurs, as in a canal boat, where a nearly vertical side joins a nearly flat bottom.

• A contrivance, usually of brass or iron, and furnished with points, worn to protect the hand, to add force to a blow, and to disfigure the person struck; a knuckle duster.

  "brass knuckles"

• The rounded point where a flat changes to a slope on a piste.

Meaning

• To apply pressure, or rub or massage with one's knuckles.

  "He knuckled the sleep from his eyes."

• To bend the fingers.

• To touch one's forehead as a mark of respect.

• To yield.